Targeted at learning about inflammatory eye diseases, this project continued to focus on ocular antigens capable of initiating pathogenic autoimmune processes in the eye, the disease processes, and mechanisms that modulate such diseases. The major achievements from the project in fiscal year 1995 include the following: (1) We showed for the first time that cellular immunity against recoverin may develop in patients with diseases such as cancer-associated retinopathy (CAR); previous studies detected only antibodies against this protein. (2) The pathogenicity of a peptide derived from the retinal interphotoreceptor retinoid-binding protein (IRBP) was increased by substituting certain residues with amino acids known to be responsible for the interaction with antigen-presenting cells. Substitution of two residues increased the pathogenicity 10,000-fold. (3) The state of immunotolerance in transgenic (Tg) mice that express a foreign antigen (hen egg lysozyme (HEL)) in their lens (HEL-Tg mice) was analyzed. The presence of HEL in the eyes was found not to be essential for the maintenance of tolerance because the unresponsiveness was retained for at least 10 months following enucleation. This observation and the finding of minute amounts of HEL in the thymus suggest that the tolerance is induced by elimination of HEL-specific lymphocytes in the thymus (= central tolerance). (4) A line of double-Tg mice was generated by mating the HEL-Tg mice with Tg mice in which most B-lymphocytes produce antibodies against HEL (Ig-Tg mice). The B-cell compartment of the double-Tg mice was identical to that of their parental Ig-Tg mice, thus suggesting that this compartment is not affected by the presence of HEL in the eyes and thymus of these mice. On the other hand, the T-cell response of the double Tg mice showed a state of partial tolerance. (5) The HEL-Tg mice were used to develop a novel model of lens-induced uveitis, produced by injecting these mice with lymphocytes sensitized against HEL. The new model is cell-mediated, unlike the previously described model for lens-induced uveitis that is mediated by antibodies.